LED Light Bulb Guide - Introduction
Ideally lighting sources should be small, efficient and long-lived. Research has been driven by these principles and today, more lighting sources with these properties are available on the market.
Made from synthetic materials, currently, only light emitting diodes (LEDs) are able to combine these three demands effectively. No other light source is as small whilst providing light output and efficiency comparable to larger, traditional light sources.
Originally used for indicator lights and as novelty lighting, LED light bulbs have now become standard in many applications, such as in car brake lights, indicators and headlights. The light gains from LED light bulbs continue to grow, and with this growth, the number of applications also grows. They already compare favourably with halogen and filament light sources and will soon overtake CFL lamps as the energy-efficient lighting source of choice. Now the standard in display lighting, LED will go some way to solving energy problems around the world, from roadside illumination to home lighting.
With lifetimes of up to 50,000 hours, LED light bulbs are one the of the longest-lived light sources on the market. This has resulted in a change of approach to designing and installing light fittings – in some situations the fiting and LED source are both discarded at the end of the LED’s lifetime.
The LED Light Source
In traditional lighting sources, light is produced by heating a metal filament, gas discharge or by converting ultraviolet radiation through fluorescence. LEDs produce light by exciting a semiconductor crystal which is a maximum of 1mm in size.
To protect the crystal, the semiconductor crystal is set into a housing, constructed in such a way that the light is emitted from the diode in an arc of around 160-180 degrees. Controlling the direction of light is easier than in traditional lighting sources since traditional sources radiate in all directions. The choice of housing affects the performance of the LED with varying degrees of cost in producing these housings. Heat is also generated by the production of light and as such steps must be taken to dissipate excess heat.
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